triple-output stepdown switching regulator
Triple-output stepdown switching regulator IC
News Release from:
Allegro MicroSystems Europe Ltd
16 April 2008
The new A4490 from Allegro MicroSystems Europe is a triple-output stepdown switching regulator integrated circuit providing three high-current outputs that are adjustable from 0.8 V to 5 V with a maximum current of 2 A.
Operating from an input voltage range of 4.5 V to 34 V, the A4490 uses multiphase switching to reduce electromagnetic interference and minimise stress on the input capacitors by interleaving the turn-on cycle of the regulators.
Features like soft start, power-on reset output and a small 4 x 4 mm QFN package make this new device an ideal choice for many portable, office automation and consumer applications.
The A4490 uses 550 kHz fixed frequency switching which allows the selection of small, inexpensive inductors and ceramic output capacitors. A charge pump is used to provide the supply to drive the power switches to ensure operation at very wide operating duty cycles and to avoid the need for power draining clamp circuits.
A power-on-reset circuit with programmable delay indicates when enabled regulators are in specification. The power-on reset flag also indicates when the input voltage drops below specification, giving the system controller advance warning while the switching circuits continue to operate down to the shutdown level. Internal diagnostics provide comprehensive protection against overloads, input undervoltages and overtemperature effects.
The Allegro A4490 is supplied in a low profile (0.75 mm) 4 x 4 mm, 20-pin QFN package with exposed power tab.